Phenolic constituents of the aerial parts of Impatiens glandulifera Royle (Balsaminaceae) and their antioxidant activities.

As a continuation of investigating Impatiens L. genus, eight flavonoids, eriodyctiol, eriodyctiol 7-O-β-ᴅ-glucoside, kaempferol 3-O-β-ᴅ-glucoside, kaempferol 3-O-β-ᴅ-galactoside, kaempferol 3-rhamnosyl-di-glucoside, kaempferol 3-O-β-ᴅ-rutinoside, quercetin 3-O-β-ᴅ-glucoside and quercetin 3-O-β-ᴅ-galactoside, two phenolic acids - p-hydroxybenzoic acid and protocatechuic acid, and 2-methoxynaphthalene-1,4-dione were isolated from the aerial parts of I. glandulifera collected in Poland. The structures of the compounds were established by analysis of their spectroscopic (1H and 13C NMR) and spectrometric (MS) data, as well as by comparison of these with those reported in the literature. Quercetin 3-O-β-ᴅ-glucoside, kaempferol 3-O-β-ᴅ-galactoside and kaempferol 3-O-β-ᴅ-rutinoside were isolated for the first time from the investigated taxon. In addition, the antioxidant activities in different tests of all obtained compounds were evaluated. The results clearly showed that among analyzed constituents, quercetin 3-O-β-ᴅ-glucoside exhibited antioxidant activity comparable or better than ascorbic acid and Trolox which were used as a positive control.